Definition of dream could be different between people's thought. Some people think dream is not real and they don't care about dreams; Some people think it's meaningful and it could relate to real life ; Some people think it's something that we wanted to happen; Some people think it's like a vision of future. The last one is what I think is true because I have been experiencing this. When I am doing something, it feels like it happened before of it happened in my dream and it feels so awkward for me.
I remember this happened to me. I went to bed and I was very tired, I fall asleep less than 10 seconds. Suddenly, my mind's all clear but my body can't move at all and that scared me. I told myself to sleep since there were school the second day. Turned asleep, same thing happened to me again, heard a woman screaming, my ears' full of pain, it felt like someone is on me, my eyes and my body couldn't move. I guess it turned out I got too tired than I fall asleep until i got up. I kept asking myself if it's really happened to me or it's just a dream. Some people say it's because "Your mind waked up, but the muscles of your body didn't catch up that fast, that's why you couldn't move." And I heard some Chinese people says it's because "A ghost was pressing you down." but it feels so unrealistic to me.
I saw a person posted what he saw in a dream to a forum and ask if anyone knows what's the meaning of the dream. It is a forum from Hong Kong and people told him to go out to find some old people that knows how to "answer meaning of the dream." I was being curious about that so I kept reading. They said, "a dream could be meaningful if you still remember what was happening, it can tells if you are going to face a big situation, in danger, or some other things that could be happen and it's relate you or your relations.